This invention relates to a mount for a light emitting device wherein light radiated from a light emitting element such as a semiconductor laser or a high intensity light emitting diode is introduced into an optical waveguide such as optical fiber at a high efficiency and is used for communication or for any other purpose.
In recent years, researches have been made on systems in which the optical communication is conducted by employing a semiconductor laser, a high intensity light emitting diode or the like as a light source and laying optical fibers instead of electric wires.
FIGS. 1A and 1B illustrate an example of a light source portion in an optical communication system of this type. FIG. 1A is a plan view, while FIG. 1B is a partial bird's-eye view.
The illustrated structure is such that a light emitting element 3 such as semiconductor laser and high intensity light emitting diode, an optical fiber for signals 7 which receives and propagates light radiated from the light emitting element 3, a cylindrical lens 8 which introduces the light radiated from the light emitting element 3 into the optical fiber 7 at a high efficiency, an optical fiber 4 for monitoring the operating state of the light emitting element 3, etc. are integrally assembled in an airtightly sealed case 1.
Accordingly, the airtight case 1 in the prior art is comparatively large in size as shown in FIG. 1A. This inevitably makes a lead wire 5 as well as a current injection terminal 6 long. The inductance of the lead wire therefore becomes high, and the high inductance is sometimes inconvenient for modulating the light emitting element at a high frequency. The large size of the case 1 is disadvantageous in the production cost, handling, etc.
Further, as seen from FIG. 1B, the signal optical fiber 7 and the cylindrical lens 8 are merely bonded to a mount 2 with indium (In) solder. The adhesiveness of the bonding is low and lacks in reliability.